JPS6152375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner equipped with a device for estimating outdoor temperature.

Conventionally, in separate air conditioners, etc.
For example, an outdoor temperature detector using a temperature sensing element such as a thermistor is installed on the outer wall of the outdoor unit, and the detected amount is used to display the outdoor temperature on the indoor unit or to control the indoor temperature according to the outdoor temperature. was being carried out.

However, such outdoor temperature detectors usually have air circulation holes all over the surface and a waterproof thermistor placed inside a white-painted case, so they cannot be exposed to direct sunlight. In addition to not being able to sufficiently eliminate the effects of heat radiation such as heat radiation, etc., it also has the drawback that deterioration due to rain and dew and the heat radiation described above is severe.

Additionally, if the wiring for the thermistor is bundled with the power line, noise from the power line will enter and cause malfunctions, so separate wiring is required, which also requires additional work. Ta.

This invention aims to improve the above-mentioned drawbacks.

FIG. 1 is a refrigerant and electric circuit diagram showing an embodiment of the present invention. In the figure, 1 is an indoor unit;
2 is a first heat exchanger that exchanges heat between the refrigerant and indoor air, 3 is a first blower that blows air to the first heat exchanger 2, 4 is an outdoor unit, and 5 is a unit that exchanges heat between the refrigerant and the outdoor air. 6 is a second blower that blows air to the second heat exchanger 5; 7 is an electric compressor that compresses the refrigerant; 8 is a pressure reducing valve; Exchangers 2 and 5 are compressor 7 and pressure reducing valve 8
Together with the refrigerant pipes A, B, C, D, etc., it forms a heat pump type refrigeration cycle (circuit).

Further, 9 is an indoor temperature sensor placed on the indoor air suction side of the heat exchanger 2, and 10 is a refrigerant pressure sensor placed in the vicinity of the heat exchanger 2 in the pipe A. The refrigerant pressure is configured to be able to be detected as an electrical output by changing the tension of a pressure sensing element such as. Also,
The temperature sensor 9 is also capable of obtaining electrical output, and the outputs of both detectors 9 and 10 and the room temperature setting device 1
3 is connected to the input side of an outdoor temperature estimation control device 12 (hereinafter abbreviated as the estimation control device), and the compressor 7 is connected to the output side.

Next, to explain the details of the estimation control device 12 with reference to FIG. 4, a constant DC voltage is applied to the indoor temperature detector 9 made of a thermistor etc. via a resistor 21, and the voltage changes depending on the temperature. The pressure detector 10 is also connected to the multiplexer 31 (multipoint switch), and the output of the indoor temperature setting device 13 consisting of the variable resistor 20 is also connected to the multiplexer 31 . The output signal is converted by an analog/digital converter 32 and inputted via an input interface 33 to a CPU 30 consisting of a microprocessor. The CPU 30 uses the program and data stored in the memory 35 connected thereto to calculate the outdoor temperature as described below, compares the room temperature with the set room temperature, and outputs the information to the relay 22 via the output interface 34. ON/OFF
and controls the operation/stop of the compressor 7 connected to this contact.

Next, the operation of this device will be described using as an example a cooling operation in which the refrigerant flows in the direction of the solid arrow.

The refrigerant gas that has exited the first heat exchanger 2, which operates as an evaporator, is compressed by the compressor 7, becomes a high-temperature, high-pressure gas body in the pipe C, and is converted into a high-temperature, high-pressure gas body in the second heat exchanger 5 by outdoor air. Cools and liquefies. that time,
If the air volume Vo blown by the blower 6 is constant, the higher the outside air temperature To, the higher the temperature of the refrigerant, and this relationship is maintained even after passing through the pressure reducing valve 8, and the position of the pressure detector 10 The refrigerant temperature Te is a function of the outside air temperature To. Further, when the refrigerant evaporates in the first heat exchanger 2, it takes heat from the indoor air, so the refrigerant temperature Te becomes higher as the indoor temperature T _R increases. That is, blowers 3, 6
The shape of the function differs depending on the air flow volume V _R and Vo, but the refrigerant temperature Te at the position of the pressure detector 10 is a function of the indoor and outdoor temperatures T _R and To, Te=a ₁ ×T _R +a ₂ The following relationship holds: ×To−a ₃ (1) (a ₁ , a ₂ , and a ₃ are constants). And an example of this constant is
a ₁ =0.544129, a ₂ =0.182816, a ₃ =9.06843. If the type and specifications of the air conditioner are constant, the constants a ₁ to _{a 3} of this relational expression (1) can be determined as an experimental formula for each combination of the air flow volumes V _R and Vo.
FIG. 2 shows a simplified example of these. In the figure, To _1, etc. is the outdoor temperature, and To ₁ <
There is a relationship of To ₂ < To ₃ .

On the other hand, there is a unique functional relationship between the refrigerant temperature and the refrigerant pressure, and the refrigerant temperature Te and the detector 10
Between the detected pressure P and The relational expression (2) holds true. And an example of this constant is a ₄ = 103427, a ₅ = 1, a ₆ = 3, a ₇ = 0.686943,
a ₈ = 117.187.

In this embodiment, the amount of air blown by the blower 3 V _R
There are three fixed amounts: strong, medium, and weak, and the amount of air blown by the blower 6 Vo is fixed in two ways: strong and weak. Therefore, the six relational expressions (1) and relational expressions (2) based on their combinations can be expressed as outdoor temperature. The estimation device 12 stores them in memory, and the indoor temperature detector 9 detects the indoor temperature T _R and the refrigerant pressure detector 10 detects the refrigerant pressure P, and inputs these detected amounts T _R and P into the estimation device 12. For example, the outdoor temperature To can be calculated using the relational expressions (1) and (2), and a signal corresponding to the outdoor temperature To can be obtained as the output of the estimation device 12.

Using this output signal, the control device 14:
By changing the set temperature of the thermostat 13 that controls the operation and stop of the compressor 7, the outdoor temperature can be changed.
The indoor temperature T _R can be adjusted according to To.

The details of the operation according to the embodiment of the invention described above will now be explained using a float chart. Fifth
The figure is a flowchart explaining the flow of calculation control, in which the indoor temperature 9 is determined in step 40,
In step 1, a refrigerant pressure of 10 is applied, and in step 42, the outdoor temperature is calculated and estimated using both. Step 43
In step 44, the set room temperature is read, and in step 44, the set room temperature is changed based on the estimated outdoor temperature. In step 45, the room temperature is compared with the changed set room temperature. If the temperature is higher than the set room temperature, the process goes to step 46 and the compressor 7 is operated; if it is lower, the process goes to step 45 and the compressor 7 is stopped. The above flow will be repeated at predetermined intervals.

Especially in stores where customers stay for a short time,
When the outdoor temperature To is high, the user feels comfortable even if the indoor temperature T _R is relatively high, so if the control device 14 is configured so that the indoor temperature T _R rises and falls with the outdoor temperature To, an energy saving effect can be obtained.

In order to adjust the indoor temperature T _R , the amount of air blown by at least one of the blowers 3 and 6 may be controlled.

In addition, the output signal of the estimating device 12 can be used to control auxiliary cooling/heating devices such as auxiliary exchangers and heaters used during rapid operation or overload during cooling/heating, or heating elements for air after dehumidifying a dehumidifier. Various things can be considered, such as a defrosting command for the device or the heat exchanger 5 during heating.

In addition, instead of performing automatic control based on the output signal of the estimation device 12 as in each of the above embodiments, the outdoor temperature To is displayed on the display provided on the indoor unit 1 using the output signal, so that the user can You can manually adjust the room temperature according to your preference, or even when using automatic control, it is convenient to display the outdoor temperature To on the display.

The present inventors designed a structure as shown in Fig. 1,
When the indoor relative humidity is below 50%, the outdoor temperature To
It was possible to estimate the outdoor temperature To with an error of less than ±2°C in the range of 27 to 45°C.

When the pressure sensor 10 is installed indoors in this way, unlike conventional outdoor temperature sensors, errors due to heat radiation do not occur, and deterioration due to rain and dew or heat radiation does not occur. Further, there is no need to perform any special wiring work.

Furthermore, if the refrigerant pressure detector 10 is installed in the part of the pipe D on the refrigerant outflow side of the second heat exchanger 5, the refrigerant will be the one that has just exchanged heat with the outside air, so there will be no disturbance during the process. Therefore, the outdoor temperature To can be estimated with an error of ±1.5°C or less. In this case, there is no problem if the pipe D is located indoors, but if the pipe D is located outdoors, it is difficult to obtain the same effect as if it is located indoors. but,
As long as the pipe D is not located too far from the indoor unit 1, a pair of diaphragms should be provided in the part that contacts the refrigerant and the part that converts the electrical output, and there should be a low vapor pressure material such as silicone oil between the two diaphragms. By using the pressure sensor 10, which has a pressure transmission part whose body is sealed and whose part is well insulated, it can be carried out simultaneously with conventional piping and wiring work.
No special construction work is required. Moreover, since there is no need for outdoor air to flow through the connection between the pressure transmission section and the pipe D as in conventional outdoor temperature detectors, complete hermetic insulation can be easily achieved. Therefore, no deterioration or error occurs in that part.

In the above embodiment, the refrigerant pressure sensor 10
Although we have explained the case where the detector 10 is installed in pipes A and D, the installation position of the detector 10 is not limited to these positions, and it can be Although the accuracy of will vary, it is possible to estimate the outdoor temperature To in any case during the refrigeration cycle. Further, the room temperature detector 9 is not necessarily limited to the suction side of the heat exchanger 2, but may be placed at a position where room temperature can be detected.

In the above example, the experimental results were explained when the indoor humidity was 50%, but when the humidity was 70%.
When the temperature reaches , the estimation error of the outdoor temperature To increases rapidly.
This is because the influence of the latent heat of the moisture condensed in the heat exchanger 2 on the refrigerant temperature Te has become evident. Figure 3 shows the relationship in a simplified manner, where RH ₁ , etc. indicates the relative humidity in the room, and RH ₁ < RH ₂
There is a relationship between

That is, under humid conditions, the refrigerant temperature Te
is not only a function of the indoor and outdoor temperatures T _R and To, but also includes the indoor relative humidity RH, Te=a ₁₀ ×T _R +a ₁₁ ×To−a ₁₂ ×RH− _{a 13} ( ₃ ) is a constant), we have to consider the relational expression (3). And an example of this constant is a ₁₀ = 0.55797, a ₁₁ =
0.192396, a ₁₂ = 0.0415121, a ₁₃ = 7.63610.

Various methods can be considered to eliminate the error caused by the humidity RH, the first of which is to provide an indoor humidity detector 11 shown by a dashed line in FIG. There are several other methods for this method, such as one in which the amount of heat of condensation is calculated theoretically from the detected amount of humidity and a correction is made to the refrigerant temperature Te determined from the actually measured refrigerant pressure P, and one in which the experimental formula There is a method to obtain an empirical formula by providing a humidity RH term (not necessarily only a first-order term) in advance.

Another method is to measure the indoor wet bulb temperature and find an empirical formula that includes the detected amount.
A method in which a pair of indoor temperature detectors 9 are provided on the indoor air suction side and the discharge side of the heat exchanger 2, and the humidity RH is determined from the temperature difference therebetween, the air flow rate _VR , and the cooling capacity determined from the refrigerant pressure P. There is also.

In addition, a pair of indoor temperature detectors 9 are provided on the indoor air suction side and the discharge side of the heat exchanger 2, and
A pair of refrigerant pressure detectors 10 are installed in the portions of piping A and B near the heat exchanger 2, and an experimental formula using the detected amounts of these four detectors 9 and 10 is determined. Humidity when calculating temperature To
Even when RH is high, outdoor temperature To can be estimated with good accuracy.

By the way, according to the experiments conducted by the present inventors, the humidity RH
70%, it was possible to estimate the outdoor temperature To within the range of 27 to 45°C with an error of ±1°C or less.

As explained above, the present invention estimates the outdoor temperature using the detected quantities of the indoor temperature sensor and the refrigerant pressure sensor, and thereby achieves This has the effect of providing an air conditioner that is highly reliable, unaffected by direct sunlight, rain and dew, etc., and that requires simple wiring and piping work.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant and electrical circuit diagram showing one embodiment of this invention, Figs. 2 and 3 are graphs for explaining the principle of this invention, and Fig. 4 is an electrical circuit diagram of the circuit shown in Fig. 2. FIG. 5 is a detailed block diagram of the circuit and is a flowchart for explaining the operation of the embodiment of the present invention. In the figure, 2 is a first heat exchanger, 3 is a first blower, 5 is a second heat exchanger, 6 is a second blower, 7 is a compressor, 9 is an indoor temperature sensor, and 10 is a refrigerant. 11 is an indoor humidity detector, 12 is an outdoor temperature estimation device, 13 is a heat sensitive body for adjusting indoor temperature,
A, B, C, D are refrigerant pipes, Te is refrigerant temperature, T _R
is the indoor temperature, To ₁ to _{To 3} are the outdoor temperature, and RH ₁ and RH ₂ are the indoor relative humidity. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first heat exchanger that exchanges heat between the refrigerant and indoor air, forming a refrigeration cycle together with this heat exchanger, and exchanging heat between the refrigerant and outdoor air. A second heat exchanger, an indoor temperature detector that detects the temperature of the indoor air, a refrigerant pressure sensor that detects the pressure of the refrigerant, and an output signal according to the outdoor temperature based on the detection amount of each of the above detectors. An air conditioner equipped with a device for estimating the outdoor temperature generated. 2. The air conditioner according to claim 1, further comprising a control device that adjusts the indoor temperature in response to the output signal of the outdoor temperature estimating device. 3. The air conditioner according to claim 2, characterized in that the control device is configured to control the set temperature of a heat sensitive element for indoor temperature adjustment that controls the operation and stop of a compressor that compresses refrigerant. . 4. The air conditioner according to claim 2 or 3, wherein the control device is configured to control the amount of air blown to the first heat exchanger. 5. The air conditioner according to any one of claims 2 to 4, wherein the control device is configured to control the amount of air blown to the second heat exchanger. 6. The air conditioner according to any one of claims 2 to 5, which has an auxiliary cooling device for adjusting indoor temperature, and wherein the cooling device is controlled by a control device. harmonization device. 7. Any one of claims 2 to 6, characterized in that the set temperature of a control device for adjusting indoor temperature is raised or lowered in accordance with the height of the estimated outdoor temperature by the outdoor temperature estimating device. The air conditioner described. 8. The air conditioner according to claim 1 or 2, wherein the outdoor temperature is displayed by an output signal of an outdoor temperature estimating device. 9 Claims 1, 2, or 8, characterized in that the refrigerant pressure detector is placed indoors.
Air conditioner as described in section. 10. The air conditioner according to claim 1, 2, 8, or 9, characterized in that a plurality of refrigerant pressure detectors are arranged. 11. The air conditioner according to claim 10, characterized in that a refrigerant pressure detector is provided on each of the refrigerant inflow side and the refrigerant outflow side of the first heat exchanger. 12. The air according to claim 1, 2, 8, 9, or 10, characterized in that a refrigerant pressure detector is provided on the refrigerant outflow side of the second heat exchanger. harmonization device. 13 Claims 1, 2, and 8 characterized in that a plurality of indoor temperature detectors are arranged.
The air conditioner according to item 9, item 10, or item 12. 14. The air conditioner according to claim 13, characterized in that an indoor temperature sensor is provided on each of the indoor air suction side and the indoor air discharge side of the first heat exchanger. 15 Claims 1, 2, 8, 9, and 1, characterized in that the indoor temperature sensor is one that detects the wet bulb temperature of indoor air.
The air conditioner according to item 0, 12 or 13. 16 A first heat exchanger that exchanges heat between the refrigerant and indoor air, and a second heat exchanger that forms a refrigeration cycle with this heat exchanger and exchanges heat between the refrigerant and indoor air. , an indoor temperature sensor that detects the temperature of the indoor air, an indoor humidity sensor that detects the humidity of the indoor air, a refrigerant pressure sensor that detects the pressure of the refrigerant, and the detected amount of each of the above detectors. An air conditioner equipped with an outdoor temperature estimation device that generates an output signal according to temperature.